CancelEventArgs Class
Updated: August 2008
Provides data for a cancelable event.
Assembly: System (in System.dll)
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The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
A cancelable event is raised by a component when it is about to perform an action that can be canceled, such as the Closing event of a Form.
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The Closing event is deprecated and has been replaced by FormClosing. It is offered as an example here only to illustrate the usage of CancelEventArgs. |
CancelEventArgs provides the Cancel property to indicate whether the event should be canceled.
The following example uses CancelEventArgs and a CancelEventHandler to handle the Closing event of a Form. This code assumes that you have created a Form with a class-level Boolean variable named isDataSaved. It also assumes that you have added a statement to invoke the OtherInitialize method from the form's Load method or the constructor (after the call to InitializeComponent).
' Call this method from the Load method of your form. Private Sub OtherInitialize() ' Exchange commented line and note the difference. Me.isDataSaved = True 'Me.isDataSaved = False End Sub 'OtherInitialize Private Sub Form1_Closing(sender As Object, e As _ System.ComponentModel.CancelEventArgs) Handles MyBase.Closing If Not isDataSaved Then e.Cancel = True MessageBox.Show("You must save first.") Else e.Cancel = False MessageBox.Show("Goodbye.") End If End Sub 'Form1_Closing
System.EventArgs
System.ComponentModel.CancelEventArgs
Microsoft.VisualBasic.ApplicationServices.StartupEventArgs
System.ComponentModel.DoWorkEventArgs
System.Configuration.SettingChangingEventArgs
System.Drawing.Printing.PrintEventArgs
System.Web.UI.WebControls.DetailsViewDeleteEventArgs
System.Web.UI.WebControls.DetailsViewInsertEventArgs
System.Web.UI.WebControls.DetailsViewModeEventArgs
System.Web.UI.WebControls.DetailsViewPageEventArgs
System.Web.UI.WebControls.DetailsViewUpdateEventArgs
System.Web.UI.WebControls.FormViewDeleteEventArgs
System.Web.UI.WebControls.FormViewInsertEventArgs
System.Web.UI.WebControls.FormViewModeEventArgs
System.Web.UI.WebControls.FormViewPageEventArgs
System.Web.UI.WebControls.FormViewUpdateEventArgs
System.Web.UI.WebControls.GridViewCancelEditEventArgs
System.Web.UI.WebControls.GridViewDeleteEventArgs
System.Web.UI.WebControls.GridViewEditEventArgs
System.Web.UI.WebControls.GridViewPageEventArgs
System.Web.UI.WebControls.GridViewSelectEventArgs
System.Web.UI.WebControls.GridViewSortEventArgs
System.Web.UI.WebControls.GridViewUpdateEventArgs
System.Web.UI.WebControls.LinqDataSourceDeleteEventArgs
System.Web.UI.WebControls.LinqDataSourceDisposeEventArgs
System.Web.UI.WebControls.LinqDataSourceInsertEventArgs
System.Web.UI.WebControls.LinqDataSourceSelectEventArgs
System.Web.UI.WebControls.LinqDataSourceUpdateEventArgs
System.Web.UI.WebControls.ListViewCancelEventArgs
System.Web.UI.WebControls.ListViewDeleteEventArgs
System.Web.UI.WebControls.ListViewEditEventArgs
System.Web.UI.WebControls.ListViewInsertEventArgs
System.Web.UI.WebControls.ListViewSelectEventArgs
System.Web.UI.WebControls.ListViewSortEventArgs
System.Web.UI.WebControls.ListViewUpdateEventArgs
System.Web.UI.WebControls.ObjectDataSourceDisposingEventArgs
System.Web.UI.WebControls.ObjectDataSourceFilteringEventArgs
System.Web.UI.WebControls.ObjectDataSourceMethodEventArgs
System.Web.UI.WebControls.SqlDataSourceCommandEventArgs
System.Web.UI.WebControls.SqlDataSourceFilteringEventArgs
System.Web.UI.WebControls.WebParts.WebPartCancelEventArgs
System.Web.UI.WebControls.WebParts.WebPartConnectionsCancelEventArgs
System.Web.UI.WebControls.WebParts.WebPartDisplayModeCancelEventArgs
System.Windows.Controls.InkCanvasSelectionChangingEventArgs
System.Windows.Controls.InkCanvasSelectionEditingEventArgs
System.Windows.Controls.InkCanvasStrokeErasingEventArgs
System.Windows.Forms.BindingCompleteEventArgs
System.Windows.Forms.ColumnReorderedEventArgs
System.Windows.Forms.ColumnWidthChangingEventArgs
System.Windows.Forms.DataGridViewCellCancelEventArgs
System.Windows.Forms.DataGridViewCellValidatingEventArgs
System.Windows.Forms.DataGridViewRowCancelEventArgs
System.Windows.Forms.FormClosingEventArgs
System.Windows.Forms.InputLanguageChangingEventArgs
System.Windows.Forms.PopupEventArgs
System.Windows.Forms.SplitterCancelEventArgs
System.Windows.Forms.TabControlCancelEventArgs
System.Windows.Forms.ToolStripDropDownClosingEventArgs
System.Windows.Forms.TreeViewCancelEventArgs
System.Windows.Forms.WebBrowserNavigatingEventArgs
System.Windows.Navigation.NavigatingCancelEventArgs
System.Windows.SessionEndingCancelEventArgs
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Date | History | Reason |
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August 2008 | Added note about FormClosing. | Information enhancement. |
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